30 



BULLETIN 244, U. S. DEPAETMENT OF AGBIC ULTTJKE. 



young shortleaf and erroneously mistaken for true annual rings of 

 growth. 



Diameters throughout this bulletin, unless otherwise stated, are 

 measured at breast height (4£ feet above the ground). Table 10 

 shows the diameter growth based on age for the Piedmont region of 

 North Carolina and for western Arkansas. The tables may be con- 

 sidered as broadly applicable to large areas within the two specified 

 regions, since differences in growth over large areas are not important 

 except as caused by local variation in quality of situation. 



Table 10. — Diameter growth of shortleaf pine, on the basis of age, in Arkansas and North 



Carolina. 1 



WESTERN ARKANSAS. 



Age (years). 



Diameter breast high. 



Age (years). 



Diameter breast high. 



Maximum. 



Average. 



Minimum. 



Maximum. 



Average. 



Minimum. 



20 



Inches. 



7.2 



8.6 



9.9 



11.0 



12.0 



12.8 



13.6 



14.4 



15.1 



15.7 



16.3 



16.9 



17.5 



18.0 



Inches. 



5.7 



7.0 



8.1 



9.1 



10.1 



10.9 



11.7 



12.3 



12.9 



13.5 



14.0 



14.5 



15.0 



15.5 



Inches. 



4.3 



5.4 



6.4 



7.4 



8.2 



9.0 



9.7 



10.3 



10.8 



11.3 



11.8 



12.2 



12.6 



12.9 



90 



Inches. 

 18.5 

 19.0 

 19.4 

 20.3 

 21.1 

 21.7 

 22.3 

 22.8 

 23.2 

 23.6 

 23.9 

 24.1 

 24.3 



Inches. 

 15.9 

 16.3 

 16.6 

 17.3 

 17.8 

 18.3 

 18.7 

 19.0 

 19.3 

 19.6 

 19.7 

 19.9 

 20.1 



Inches. 

 13.3 



25 



95 



13.6 



30 



100 



13.8 



35... 



110 



14.2 



40... 



120 



14.6 



45 



130 



14.9 



50 



140 



15.1 



55 



150 



15.3 



60... 



160 



15.4 



65 



170 



15.5 



70 



180 



15.6 



75 



190 



15.7 



80 



200 



15.8 



85 











PIEDMONT REGION, NORTH CAROLINA. 



2.0 

 5.9 



0.9 

 3.0 





0.6 



9.2 



4.9 



1.2 



11.6 



6.3 



1.8 



13.3 



7.5 



2.4 



14.5 



8.4 



3.0 



15.6 



9.2 



3.5 



16.5 



9.9 



4.0 



45 



17.1 

 17.6 

 18.0 

 18.4 

 18.7 

 19.0 

 19.2 

 19.4 



10.5 

 11.0 

 11.4 

 11.7 

 12.1 

 12.4 

 12.7 

 13.0 



50 



55 



60 



65 



70 



75... 



80 





4.5 

 5.0 

 5.4 

 5.8 

 6.1 

 6.4 

 6.8 

 7.1 



1 The table for Arkansas is based on breast-high diameter measurements of 285 trees and 34 trees repre- 

 senting the average of even-aged plots; the North Carolina tablo is based on decade measurements on 332 

 stumps, 26 to 89 years old. 



The close relation between tree density and growth in diameter is 

 illustrated in Table 11, compiled from measurements on unit areas 

 of different density of trees of a 30-year-old fully stocked shortleaf 

 stand. In seven consecutive sample areas of one-tenth acre each, 

 the size of the diameter class prevailing on each plot increased regu- 

 larly with a corresponding regular decrease in tho number of trees 

 per acre. So far as is known this close relation holds true for all 

 pure stands of shortleaf pine. 



